This invention relates to a development of the brake actuating means described in my U.S. Pat. Nos. 4,199,046 and 4,313,530, which are the most pertinent art known to me. A further impression of the state of the art relating to actuators of the same general type may be obtained by considering the references discussed in the specifications of those patents or cited during their prosecution.
In the actuators described in my prior patents, a one-way clutch element acting on the pedal crankshaft of a bicycle is formed by a spiral coil spring having a central bight engaging a yoke through which braking forces are transmitted, and oppositely handed spiral coils surrounding the crankshaft and extending axially outward along the crankshaft from opposite sides of the yoke. Outward portions of the coils are of relatively lighter gauge and are normally the only portions to engage the crankshaft, thus reducing frictional drag. Development has shown that this arrangement can operate very satisfactorily with very little drag during forward pedalling of the bicycle whilst requiring very little rearward angular motion of the pedals to produce engagement.
Much thought has been given to alternatives to this spring type brake actuator as described in the above patents. Because of the space limitations in the small bottom brackets (the pedal crankshaft housing) of non-North American manufactured bicycles, I do not know of any alternative of comparable performance to my spring type actuator for such bicycles. However, for those North American manufactured bicycles that have large bottom brackets (approximately 2" inside diameter), I have devised an alternative to the above coil type brake actuator which is described in my copending U.S. patent application Ser. No. 674,292, filed Nov. 23, 1984. In the arrangement described in that application, a light spring clutch acts as a pilot actuator closing the jaws of a main clutch mechanism which then operates in a somewhat similar manner to a stillson wrench and locks an actuating lever to the pedal crankshaft. I have now developed a further alternative arrangement in which a light spring clutch acts directly of the actuating lever to provide an initial braking force the reaction from which actuates a main clutch mechanism to enable transmission of greater braking forces than could be sustained by the spring alone.